Artificial cellulosic material



Patented June 21, 1938 UNITED STATES PATENT OFFICE Friedrich Raspe and Hermann Giese, Leverkusen I. G. Werk, Germany, assignors to I .G. Farbenindustrie the-Main, Germany Aktiengesellschaft,

Frankforton- No Drawing. Application June 15, 1936, Serial No. 85,439. In Germany June 28, 1935 2 Claims.

' This invention relates to artificial cellulosic material such as silk filaments having a reduced luster or subdued luster It is a known fact that artificial cellulosic material having a reduced luster can be prepared by spinning a cellulosic solution having incorporated therewith a calcined titanium dioxide pigment or a calcined titanium dioxide containing pigment. These titanium pigments give the artificial cellulosic material prepared a desired reduced luster. On the other hand, considerable disadvantages are connected with the use of these calcined titanium pigments, in that the very hard crystal edges of the titanium dioxide wear out the metallic devices especially in the spinning process. In many cases it has further been found that the silk filaments themselves are roughened by the hard crystal edges.

In accordance with the present invention these disadvantages are overcome by delustering the artificial cellulosic material by the addition of a precipitated and dried but not calcined titanium compound to the cellulosic mass to be spun. The following advantages are thus attained: first, the

metallic devices are not worn out and second;

the silk obtained is not roughened, since the precipitated and dried titanium compound is softer than the calcined product.

A titanium compound which is obtained by hydrolysis of titanium salt solutions, especially by hydrolysis of basic titanium sulfate solutions has proved to be particularly suitable for the delustering of artificial cellulosic material such as silk filaments. The product obtained by hydrolysis is washed with an alkaline reacting solution and thereby freed from the acids adhering to the product; the washed product is then dried at a temperature of about 80to about 125 C. The product obtained in this manner contains water osmotically bound which fills up the interstices between the titanium dioxide particles in an elongated crystal lattice. It is a very soft and finely divided powder.

While when using such uncalcined product as a pigment the covering power amounts to only illustrated by the fol- .are added. The viscose solution is thenspun with the use of the usual spinning bath. In this manner an artificial cellulosic material such as silk filament with a dull luster is obtained. In the same manner also cuprammonium and acetate cellulosecan be treated.

The term artificial cellulosic material used in the description and claims is intended to comprise artificial silk and other analogous products such as artificial horse hair, threads, bands, filaments and the like.

We claim:--

1. An artificial cellulosic material possessing a dull luster and obtained from a cellulosic solution, containing a uniformly distributed delustering agent consisting of finely divided acid-free precipitated and dried but uncalcined titanium pigment in an amount between about 1% and 5% based on the weight oi cellulose in said mateerial. v

2. A spinning solution for the manufacture of dull luster. artificial cellulosic materials, comprising a solution of cellulose adapted for the preparation of artificial cellulosic materials and a deluste'ring agent consisting of finely divided acid-free precipitated and dried but uncalcined titanium pigment inan amount between about 1% and 5% based'on the weight ofcellulose in said material uniformly distributed throughout said solution. FRIEDRICH RASPE.

HERMANN GIESE. 

